Stationary Blade Two-Stage Bending for Dimensional Stability

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Solution Overview

Problem

The manufacturing of double-walled stationary blades for hair cutting appliances is hindered by high costs and inaccuracies in sheet metal processing, particularly due to resilient material properties that lead to unwanted deformations and rebound forces during bending, resulting in suboptimal contact between cutting edges.

Innovation Solution

A two-stage bending procedure is employed for a metal component, initially forming a bracket-like shape and then compensating intermediate deformations using a support insert to achieve a flat and even top wall, ensuring dimensional stability and precise contact between stationary and movable blades.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-stage bending procedure is used for sheet metal processing, then the manufacturing process is simple and cost-efficient, but the top wall exhibits unwanted deformations and rebound forces resulting in poor dimensional stability

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoiddimensional stability of top wall

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The bending process is divided into two distinct stages: a first bending procedure that forms the bracket-like shape with initial deformation, and a second bending procedure that compensates for rebound forces. This segmentation allows each stage to be optimized independently, achieving both manufacturing feasibility and dimensional precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first bending procedure intentionally creates a predetermined deformation pattern in the top wall. This preliminary action sets up the metal component in a specific intermediate state that will be corrected in the second stage, allowing the final dimensional accuracy to be achieved after compensation.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If conventional sheet metal processing is used, then manufacturing costs are reduced, but resilient material properties cause rebound forces and residual deformations

Engineering Contradiction:

Improvemanufacturing cost efficiencyVSAvoidcontact precision between cutting edges

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The resilient properties of the sheet metal material, which normally cause harmful rebound forces and deformations, are converted into a benefit by using the material's elasticity to return to a predetermined intermediate shape after the first bending. This controlled rebound becomes part of the manufacturing process rather than a defect.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of substance

If the metal component is made thin for cost efficiency, then material costs are reduced, but the component becomes more susceptible to deformation during processing

Engineering Contradiction:

Improvematerial cost reductionVSAvoidshape accuracy during bending

Core Design Contradiction:

Loss of substanceVSManufacturing precision

Solution Approach 1:

The manufacturing process parameters are changed by introducing a two-stage bending procedure with specific timing and deformation magnitudes. This allows thin metal components to be processed accurately by controlling the bending sequence and compensation forces, making the process suitable for cost-efficient thin materials.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method allows for the production of dimensionally stable stationary blades with minimal residual deformation, enhancing cutting performance by maintaining a tight contact between cutting edges while utilizing cost-efficient and conventional manufacturing processes.

Implementation Method 1

the metal component is at least slightly pretensioned in the longitudinal direction, due to the longitudinal extension of the support insert

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The second bending procedure induces a deformation that compensates for an intermediate deformation of the top wall

Methodology Applied

Scientific EffectPlastic deformation: Deformation

Data Source

PatentUS11772290B2Stationary blade and manufacturing method

Publication Date: 2023.10.03 KONINKLIJKE PHILIPS NV

AI summary

A method of manufacturing a stationary blade. A metal component is provided, and a first bending procedure is applied, forming a top wall and two legs at opposite ends of the top wall that are spaced away from one another longitudinally. Each of the two legs is arranged at a first angle with respect to the top wall, and two bending edges are formed between the top wall and the two legs. A support insert is also provided having a longitudinal extension that is at least slightly greater than a receiving space between the two bending edges. The metal component and support insert are joined, and a second bending procedure is applied to the metal component, where the two legs are further bent, thereby arranging each of the two legs at a second angle with respect to the top wall that is smaller than the first angle.